Twenty-six Egyptian soldiers were killed or wounded on Friday in attacks on checkpoints in the Sinai Peninsula where the Islamic State group is conducting an insurgency, the military said.
Security officials who requested anonymity said at least seven soldiers were killed, but it was not immediately possible to obtain an official death toll.
The military said it killed 40 assailants as it clashed with extremists in North Sinai, the main focus of the deadly IS insurgency.
Security officials said ambulances raced to the sites of the attacks south of the town of Rafah on the border with the Gaza Strip.
Jihadists have killed hundreds of policemen and soldiers in attacks in North Sinai since the military toppled Islamist president Mohamed Morsi in 2013 and launched a deadly crackdown on his supporters.
IS has also attacked tourists, killing all 224 on board a Russian plane carrying holidaymakers in 2015, as well as Christian churches elsewhere in Egypt.
The jihadists in the Sinai pledged allegiance to the Islamic State group in late 2014, establishing the self styled “Sinai Province” in the peninsula, which borders Israel as well as Gaza.
Unlike the main organisation in Syria and Iraq, they have been unable to seize population centres, with one attempt to occupy a town in 2015 ending with the military unleashing F-16 jets against the jihadists.
Instead the group has tried to keep up a steady war of attrition involving roadside bombings, sniper fire and checkpoint attacks such as the ones on Friday.